2023/12/20 by César Ayala, Ayala, César, Camilo Castro-Arriaza +3 · 1 citation
Physics and Astronomy · #Black Holes and Theoretical Physics #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.2312.13134
openalex publication_date 2023/12/20 · openalex created_date 2023/12/22 · openalex updated_date 2026/07/28
Approximate knowledge of the renormalon structure of the Bjorken polarised sum rule (BSR) Γ1\rm p-n(Q2) leads to the corresponding BSR characteristic function that allows us to evaluate the leading-twist part of BSR. In our previous work \citepPLB, this evaluation (resummation) was performed using perturbative QCD (pQCD) coupling a(Q2) ≡ αs(Q2)/π in specific renormalisation schemes. In the present paper, we continue this work, by using instead holomorphic couplings [a(Q2) ↦ \mathcal A(Q2)] that have no Landau singularities and thus require, in contrast to the pQCD case, no regularisation of the resummation formula. The D=2 and D=4 terms are included in the Operator Product Expansion (OPE) of inelastic BSR, and fits are performed to the available experimental data in a specific interval (Q2\rm min,Q2\rm max) where Q2\rm max=4.74 \rm GeV2. We needed relatively high Q2\rm min ≈ 1.7 \rm GeV2 in the pQCD case since the pQCD coupling a(Q2) has Landau singularities at Q2 \lesssim 1 \rm GeV2. Now, when holomorphic (AQCD) couplings \mathcal A(Q2) are used, no such problems occur: for the 3 δAQCD and 2 δAQCD variants the preferred values are Q2\rm min ≈ 0.6 \rm GeV2. The preferred values of αs in general cannot be unambiguously extracted, due to large uncertainties of the experimental BSR data. At a fixed value of αs^ \rm MS(MZ2), the values of the D=2 and D=4 residue parameters are determined in all cases, with the corresponding uncertainties.